Composite metallic plate.



, wi tueoom 1 C. J. THORP. COMPOSITE METALLIC PLATE. APPLlCATlON man JAN-H. 1915 LEBAM. Patented Jan.18,1916.

ilver Y CHARLES J. THORP, OF DETROIT, MICHIGAN.

COMPOSITE METALLIC PLATE.

Original application filed November 23, 1914, Serial No. 873,428. Divided Specification of Letters Patent.

Patented Jan. is, rare.

and this application filed January 11, 1915. Serial No. 1,692.

Z '0 all'whom it may concern:

Be it known that I, CHARLES J. THORP, a citizen of the United States of America, residing at Detroit, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Composite Metallic Plate, of which the following is a specification, reference being had therein to the accompanying drawings.

This is a division of my application filed Nov.

This invention relates to a composit e'me tallic plate, and the object of my invention is to provide a plate of gold and silver which can be used for various purposes, but which has been especially designed for the art of dentistry.

As illustrating an instance of the use of a plate in accordance with my invention, reference will be had to the drawing, wherein Figure 1 is a plan of a composite plate produced by a metallurgical operation; Fig. the same; Fig. 3 is a the plate, and Fig. 4 is a vertical sectional view of a tooth crown or shell produced by stamping and cupping the disk shown in Fig. 3.

Selecting a bar of gold about one quarter inch thick and 22 carat fine, and a bar of granular pure or fine silver, said silver 'is tages. In the first place, the cost of platinum placed upon the gold. The bar of silver is about the same thickness as the gold. .The bar of silver is then subjected to the action of heat, for instanceby a torch, to the extent that the bar. ofsilver is melted and soldered on the gold bar. That is, the confronting sides of the bar form a homogeneous connecting tissue without aflecting the outer sides of the ingot thus produced, the outer sides being maintained gold and silver respectively. When the silver has sufiiciently cooled, the ingot is subjected to a rolling action with sufiicient pressure brought to bear to reduce the combined bars to about thirty gage with an erguai-gage of each metal maintained or approximately so, and

23, 1914, Serial No. 873,428.

in this manner a sheet is produced having gold and silver sides designated 1 and 2 respectively. From the composite sheet or plate thus produced one or more disks or blanks 3 can be cut and stamped and then the disk or blank subjected to the action of the dies or forming members whereby the disk is stamped to form a crown or shell 4 having a silver lining. V I Considering the crown or shell from a dental standpoint, the metal composition possesses indispensable characteristics and the following may be cited :first, it reduces the amount of gold heretofore necessary in the formation of a tooth crown or shell without sacrificing strength and other prerequisites; .second, it provides a tooth crown or shell that has a lining which resists amalgamation which would occur if amalgam was used in connection with a crown composed simply of gold; third, such a composite tooth crown will resist the force and wear of mastication and thereby preclude any danger of the crown being completely Worn through, and fourth, a simple and inexpensive crown is produced that can be easily shaped to conform to the grinding or irregular surface of atooth.

I am aware that platinum has been used in connection with gold tooth crowns or shells, but suchcompositions have many disadvanprohibits extensive use. For instance, sixty dollars an ounce as compared with silver at fifty cents an ounce. Second, the-many inequalities between gold and platinum willnot permit of its being properly shaped or swaged since the melting point of platinum is much higher than that of gold, and it is simply impossible to fuse these two metals and maintain an equal gage for -each.

I, attach considerable importance to the fact that in uniting the gold and silver into a single sheet, only the confronting sides are homogeneous or composite, and the outer sides maintain their distinctive qualifications. The uniting of the confronting sides of sheets of gold and silver permits of the opposite exposed faces with one exposed face composite sheet being bent or shaped withsilver and the other exposed face gold. 10 out any danger of the two metals separating, In testimony whereof I aflix my signature as would occur if the sheets or plates were in presence of two witnesses. 5 joined by a'rolling or other process. CHARLES J. THORP. What I claim is 1 r Witnesses: A bimetallic plate, composed of goldfiand KARL H. BUTLER, silver fused together to form a plate having VICTOR G. BOND. 

